During a conventional process to manufacture a storage device, a compression tool applies force to a top cover to compress the top cover and a form-in-place-gasket (“FIPG”) to ensure that there is metal-to-metal contact between the top cover and a base unit. A metal-to-metal contact is desirable because it reduces a necessity for additional force to be applied to top cover screws to secure the top cover to the base unit. Furthermore, the compression of the top cover and the FIPG onto the base unit forms a FIPG seal, which isolates the air inside the storage device from outside the storage device to reduce contamination on one or more components within the storage device. Thus, full compression of the top cover with respect to the base unit as evidenced by the metal-to-metal contact also ensures that the FIPG seal is fully functional.
However, metal-to-metal contact between the top cover and the base unit is only desirable in certain areas, such as where the top cover screws will be used to secure the top cover to the base unit. In other areas, such as where the storage media, the disk clamp, or the head stack assembly are located, metal-to-metal contact is undesirable as such contact may damage the storage media, the disk clamp, or the head stack assembly.
Conventionally, to determine whether there is a metal-to-metal contact, an operator places a shim or paper strips between the top cover and the base unit. Then the top cover was compressed onto the base unit by the compression tool. If the operator is unable to pull out the shim or paper strips, then the top cover was considered to be sufficiently compressed onto the base unit to provide the metal-to-metal contact. Otherwise, an amount of force supplied by the compression tool was adjusted to ensure that there was sufficient compression by the top cover onto the base unit.
However, such a method was often inaccurate as the placement of the shim or paper strips altered an amount of force required to compress the top cover onto the base unit. Thus, in normal production without the shim or paper strips, the top cover may not be properly compressed onto the base unit. Furthermore, placement of the shim or paper strips inside a perimeter of the FIPG perimeter required the top cover or the base unit to be modified. In addition, such a conventional method may prove inadequate when determining whether too much compression has occurred, especially in areas inside the perimeter of the FIPG. This could lead to damage of components of the storage device, such as the storage media, the disk clamp, or the head stack assembly.
Thus, there is a need for a method and system for determining storage device top cover compression effectiveness.